ABSORPTION OF NEUTRAL PIONS PRODUCED IN SUBTHRESHOLD NUCLEUS-NUCLEUS COLLISIONS

Institute of Experimental Physics, Warsaw UniversityHoza 69, 00-681 Warszawa, Polandandthe TAPS Collaboration(Received November 17, 2005)Neutral pions produced in Ar-induced reactions at 95A MeV on C, Al,Ag and Au targets were identified through their γγ decay photons, mea-sured with TAPS spectrometerinstalled at GANIL Caen. Angular distribu-tions of neutral pions are reasonably well described within a phenomenolog-ical model of pion reabsorption, taking into account momentum-dependentabsorption length. The angular distribution of primary neutral pions(before absorption) seems to be independent of the beam energy and massnumbers of colliding nuclei. This distribution is described by the formula:1 + A